189223-81-2Relevant academic research and scientific papers
Convergent strategy towards the synthesis of restricted analogues of peloruside A
Zimmermann, Nicolas,Pinard, Pierre,Carboni, Bertrand,Gosselin, Pascal,Gaulon-Nourry, Catherine,Dujardin, Gilles,Collet, Sylvain,Lebreton, Jacques,Mathe-Allainmat, Monique
, p. 2303 - 2315 (2013/05/09)
A rapid convergent strategy to access unsaturated analogues of peloruside A has been demonstrated. This is depicted as an original C11-C12 aldol connection between a C12-C20 ketone fragment and a C2-C11 pyran fragment bearing an aldehyde function, with high yield and a good level of diastereoselectivity. The desired unsaturated macrocycle was obtained by a late-stage ring closing metathesis reaction.
A stereoselective synthesis of the C9-C19 subunit of (+)-peloruside A
Raghavan, Sadagopan,Vinoth Kumar
, p. 2847 - 2858 (2013/05/08)
The stereoselective synthesis of a C9-C19 fragment of the potent antitumor agent peloruside A is disclosed. The C11 stereogenic centre was created by a vinylogous Mukaiyama aldol reaction following Carreira's protocol, with excellent stereocontrol. The C13 stereogenic centre was introduced by a substrate controlled reduction. The C15 stereocentre was fashioned using Noyori's asymmetric transfer hydrogenation while the Z-trisubstituted double bond was formed by a regioselective hydrostannation of an alkyne followed by methylation of the resultant vinyl stannane using Lipshutz's protocol. The C18 chiral centre was introduced by a chemoenzymatic route.
Catalytic enantioselective total synthesis of (+)-torrubiellone C
Jessen, Henning J.,Schumacher, Andreas,Schmid, Fabian,Pfaltz, Andreas,Gademann, Karl
supporting information; experimental part, p. 4368 - 4370 (2011/10/18)
Silyl-protected (R)-methyl 2-(hydroxymethyl)butanoate was obtained by an enantioselective Ir-catalyzed hydrogenation in high yield and selectivity. Elaboration of this building block via Takai and Stille reactions gave a protected hydroxy polyene chain, w
Total synthesis of plakortone B
Xie, Xin-Gang,Wu, Xun-Wei,Lee, Hing-Ken,Peng, Xiao-Shui,Wong, Henry N. C.
supporting information; experimental part, p. 6933 - 6941 (2010/08/22)
Plakortone B is a naturally occurring bicyclic[3.3.0]furanolactone compound with attractive bioactivities. Although the relative configuration of plakortone B's central core had been established by NMR spectroscopic methods, the absolute configuration of its four stereocenters remained unknown. In the present paper, all four possible isomers of plakortone B were synthesized and one of these molecules was found to be identical with the natural plakortone B on the basis of 1H, 13C NMR spectra and specific rotation comparisons. Thus, the absolute configuration of the natural plakortone B was determined to be (35, 4S, 6R, 10R).
Total synthesis of rutamycin B and oligomycin C
Panek,Jain
, p. 2747 - 2756 (2007/10/03)
The asymmetric synthesis of the macrolide antibiotics (+)-rutamycin B (1) and (+)-oligomycin C (2) is described. The approach relied on the synthesis and coupling of the individual spiroketal fragments 3a and 3b with the C1-C17 polyproprionate fragment 4. The preparation of the spiroketal fragments was achieved using chiral (E)-crotylsilane bond construction methodology, which allowed the introduction of the stereogenic centers prior to spiroketalization. The present work details the synthesis of the C19-C28 and C29-C34 subunits as well as their convergent assembly through an alkylation reaction of the lithiated N,N-dimethylhydrazones 6 and 8 to afford the individual linear spiroketal intermediates 5a and 5b, respectively. After functional group adjustment, these advanced intermediates were cyclized to their respective spiroketal-coupling partners 40 and 41. The requisite polypropionate fragment was assembled in a convergent manner using asymmetric crotylation methodology for the introduction of six of the nine-stereogenic centers. The use of three consecutive crotylation reactions was used for the construction of the C3-C12 subunit 32. A Mukaiyama-type aldol reaction of 35 with the chiral α-methyl aldehyde 39 was used for the introduction of the C12-C13 stereocenters. This anti aldol finished the construction of the C3-C17 advanced intermediate 36. A two-carbon homologation completed the construction of the polypropionate fragment 38. The completion of the synthesis of the two macrolide antibiotics was accomplished by the union of two principal fragments that was achieved with an intermolecular palladium-(0) catalyzed cross-coupling reaction between the terminal vinylstannanes of the individual spiroketals 3a and 3b and the polypropionate fragment 4. The individual carboxylic acids 46 and 47 were cyclized to their respective macrocyclic lactones 48 and 49 under Yamaguchi reaction conditions. Deprotection of these macrolides completed the synthesis of the rutamycin B and oligomycin C.
A formal synthesis of brassinolide
Schmittberger,Uguen
, p. 2837 - 2840 (2007/10/03)
Enzyme-catalysed differentiation of hydroxy groups in a C(2υ)-shaped tetraol-sulfide, combined with a E-stereoconvergent Ramberg-Backlund process, allowed to prepare pure (2S))-2,3-dimethyl-1-iodobutane, which could be copled with a 3,5-cyclopregnane-20-t
